Particle copying code was already properly sharing pointcache between
orig data and its copy only when `LIB_ID_COPY_SET_COPIED_ON_WRITE` is
set, do the same for the other point cache users.
Using `LIB_ID_CREATE_NO_MAIN` here is waaaaaaay to much wide scope for
such a dangerous/advanced behavior, that kind of things has to be
strictly restricted in scope.
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